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The vibration produced by an earthquake can cause liquefaction. Liquefaction events in the wells are influenced by the nature of soil, geological environmental and earthquake characteristics, as well as other factors such as rock grain size, groundwater level and ground vibration acceleration. There were a number of cases after the Lombok earthquake which were indicative of the occurrence of liquefaction, especially those observed at the location of residents water wells. After earthquakes, we found many phenomena of dry water wells, the occurrence of siltation of wells, broken pipes in deep drill wells, and the collapse of the walls of wells. Generally the surface soil layer in Lombok is loose sand, and as is known that the loose sand layer has a higher potential for the occurrence of liquefaction due to its grain characteristics. This paper presents sand grain size analysis of wells in North and West of Lombok which undergo liquefaction when 2018 Lombok Earthquake. The result show the distribution from shieve analysis, microscope sampling results, and also distribution from laser particle size analysis. This study is essential for the further analysis to the resistance of wells to vibration of erthquakes.